Modularly Constructed Paper Machine Covering

ABSTRACT

A covering for paper machines, paperboard machines or tissue machines, which is constructed from a construction kit includes a plurality of prefabricated web-shaped material layers. Each web-shaped material layer is configured dependent upon a category and operating conditions of the covering, and the plurality of prefabricated web-shaped material layers are stacked atop one another and are joined to one another at least in sections, two-dimensionally, and in a manner that prevents the plurality of prefabricated web-shaped material layers from being detached. The invention also relates to a method for producing the inventive covering.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method for the modular production ofcoverings for paper machines, paperboard machines or tissue machines andto a covering for a paper machine, paperboard machine or tissue machine.

2. Description of the Related Art

Paper machines, paperboard machines or tissue machines have coverings inthe forming section, press section and drying section.

The different categories of coverings, namely forming meshes, pressfelts and dryer fabrics, must meet many different requirements, forexample with regard to dewatering behavior, moisture adsorption capacityand the like.

Furthermore, coverings of the same category must meet differentrequirements depending on the operating conditions. For example, therequirements for the structure of the side of a forming mesh facing thefibrous web in the production process for graphic paper differfundamentally from those for the production of tissue.

Due to the different categories of coverings described above, each ofwhich has to meet many different requirements, the historicaldevelopment has seen the manufacturers of coverings produce, forpractically every category and operating condition, a covering typewhich differs almost fundamentally from the covering types of othercategories and operating conditions.

For example, covering manufacturers often produce forming meshes withdifferent weave patterns for specific customers.

SUMMARY OF THE INVENTION

The current invention provides a method for providing coverings, as wellas coverings which are easier and cheaper to produce than thosecoverings known from the prior art.

The invention is based on the idea of reducing the production costs ofcoverings for paper machines, paperboard machines or tissue machines bysimplifying the production method for the entire product range of papermachine coverings.

The method according to the invention provides for producing differentcategories of coverings modularly from a construction kit ofprefabricated web-shaped material layers. According to the invention,several web-shaped material layers are selected from the constructionkit of prefabricated web-shaped material layers depending on thecategory and operating condition of the covering to be produced. Theweb-shaped material layers selected from the construction kit arestacked atop one another and joined to one another at least in sections,two-dimensionally, and in a manner that prevents them from beingdetached.

In other words, a method is proposed which provides a construction kitof prefabricated material layers. By defining a construction kit ofprefabricated web-shaped material layers for the entire product range ofpaper machine coverings and by selecting prefabricated web-shapedmaterial layers from the construction kit, depending on the category andthe operating conditions of the covering, the number of differentmaterial layers and, for example, weave structures is greatly reduced.

Whereas in the past a different weave structure was required for eachoperating condition for example, it is possible in accordance with theinvention to produce coverings for the different categories andoperating conditions by combining several of the prefabricatedweb-shaped material layers.

According to one embodiment, provision is made for the order in whichthe selected web-shaped material layers are stacked to depend on thecategory and the operating conditions of the covering. The flexibilityin using the prefabricated material layers is thus increased, asdifferent properties of the covering can be achieved depending on theorder in which the selected web-shaped material layers are stacked.

In this connection it should be noted that the prefabricated web-shapedmaterial layers are constructed such that they fulfill, on their own orin combinations, specific functions such as damping properties,dimensional stability, wear stability, surface properties, liquidadsorption capacity and the like.

According to another embodiment, provision is made for the constructionkit of prefabricated material layers to include at least one materiallayer influencing the surface of a fibrous web and at least onewear-stable material layer. In this case the material layer influencingthe surface of the fibrous web is understood to be the material layerwhich terminates the covering in the direction of the fibrous web.Furthermore, the wear-stable material layer is understood to be thematerial layer which terminates the covering in the direction of thepaper machine.

According to another embodiment, provision is made for the constructionkit of prefabricated material layers to include at least onedimensionally stable material layer. The dimensionally stable materiallayer can be configured either as a material layer which is constructedseparately from the two previously mentioned material layers or as anintegral component of the one or other previously mentioned materiallayers.

Various possibilities for the construction of the above-mentionedmaterial layers are conceivable.

Another embodiment of the invention provides for the material layerinfluencing the surface of the material web to be a textile or anon-textile areal structure.

Another embodiment of the invention provides furthermore for thewear-stable material layer to be a textile or a non-textile arealstructure.

Another embodiment of the invention provides for the construction kit ofprefabricated material layers to include at least one material layerinfluencing the liquid adsorption capacity. The material layerinfluencing the liquid adsorption capacity can be constructed eitherseparately from the previously mentioned material layers or as anintegral component of one of the previously mentioned material layers.

The material layer influencing the liquid adsorption capacity can beconstructed either as a material layer with a high liquid adsorptioncapacity or as a material layer with a low liquid adsorption capacity.

A material layer with a high liquid adsorption capacity should have aliquid adsorption capacity which is greater than 50% of the totalcapacity of the material layer, in particular preferably greater than70% of the total capacity of the material layer and most preferablygreater than 80% of the total capacity of the material layer.

A material layer with a low liquid adsorption capacity should have aliquid adsorption capacity which is less than 50% of the total capacityof the material layer, in particular preferably less than 30% of thetotal capacity of the material layer and most preferably less than 20%of the total capacity of the material layer.

According to another embodiment of the invention, provision is made forthe construction kit of prefabricated web-shaped material layers toinclude at least one anti-rewetting material layer.

Furthermore, other embodiments provide for the dimensionally stablematerial layer and/or the material layer influencing the liquidadsorption capacity and/or the anti-rewetting material layer to betextile or non-textile areal structures.

A textile areal structure is understood to be a weave structure or afleece or a thread plaiting or a warp knitting.

Furthermore, a non-textile areal structure is understood to be astructured and/or penetrated film or a structured and/or penetratedmembrane and/or a foamed layer.

It is advantageous, for example, for the material layer with a largeliquid adsorption capacity to be a foamed layer.

Furthermore, it is advantageous for the material layer with a smallliquid adsorption capacity to be a foamed layer or a penetrated film ora membrane.

Furthermore, it is advantageous for the foamed layer to have a definedpore size. By providing a defined pore size it is possible, for example,to establish the liquid adsorption capacity and hence the dewateringbehavior. Furthermore, it is also conceivable for the foamed layer beltto have several defined pore sizes.

According to an embodiment of the invention the foamed layer has adefined pore transverse profile (i.e., different pore sizes in thetransverse profile of the material layer). It is thus possible toselectively establish the dewatering behavior and the pressing behaviorby way of the web width of the paper machine covering, as the result ofwhich the fibrous web transverse profile can be selectively established.

A film mentioned above can be produced by an extrusion method and/or arolling method for example.

Various possibilities for joining together the several material layersselected from the construction kit are conceivable.

For example, it is possible for at least two of the material layers tobe joined together chemically. Furthermore, it is possible for at leasttwo of the material layers to be joined together mechanically and/or bymeans of a textile joining method. The different material layers of acovering according to the invention can be joined together by just oneor the other ways. However, it is also possible for the material layersto be joined together not only mechanically but also by textile andchemical ways.

For example, a first material layer of a covering according to theinvention can be joined mechanically to a second material layer and thesecond material layer can be joined chemically to a third materiallayer. Furthermore, the third material layer can be joined by a textilejoining method to a fourth material layer of this covering, with thefourth material layer being joined mechanically and chemically to afifth material layer.

According to another embodiment the chemical bond is effected by aninterface-active bond. In this connection an interface-active bond isunderstood to be a bond resulting from vulcanizing or melting or welding(i.e., ultrasonic welding). In other words, the interfaces of the twomaterial layers which are to be joined together are changed/activated insuch a way that they bond together without a bonding medium.

Another embodiment of the invention provides for the chemical bond to beeffected by introducing a bonding medium. In this case the bondingmedium can be an adhesive for example.

Furthermore it is possible for the bonding medium itself to form amaterial layer between the joined material layers, in which case thebonding medium is a foamed material layer for example, which is arrangedbetween the material layers that are joined together and bonds saidmaterial layers together.

The bonding medium constructed as a separate material layer can fulfillspecific functions on its own or in combination with one or morematerial layers. For example, by combining the bonding medium with oneor more material layers it is possible to exert an advantageousinfluence on the properties of the covering according to the invention.

If the material layers are joined together mechanically it isconceivable for them to be pressed together.

If the material layers are joined together by a textile joining methodit is possible for them to be sewn or pinned together.

If the covering is one which is not constructed of material webs in theform of endless belts, it makes sense for the various web-shapedmaterial layers which are stacked atop one another to be joinedtogether, two-dimensionally, in sections that are mutually offset inmachine direction so that the covering forms two end areas whichcomplement each other in form and function and can be joined together.Through the material layers which are mutually offset in machinedirection and joined together, two-dimensionally, in sections, thecovering forms two end areas which complement each other in form andfunction and can be joined together, two-dimensionally, so that thecovering is constructed in the form of an endless belt. Thetwo-dimensional bond between the two end areas is particularly stableand durable.

If the covering is constructed of several material layers arranged sideby side over its width, it also makes sense for the material layerswhich are stacked atop one another to be mutually offset at least insections transverse to the machine direction so that above and/or underneighboring material layers of a certain layer of the covering there isalways a material layer which overlaps with both material layersarranged side by side.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of (an) embodiment(s) of the invention taken in conjunctionwith the accompanying drawing(s), wherein:

FIG. 1 is a detail in longitudinal section of a forming mesh accordingto the invention,

FIG. 2 is a detail in longitudinal section of a press felt according tothe invention,

FIG. 3 is a detail in longitudinal section of a dryer fabric accordingto the invention,

FIG. 4 is shows the two end areas of the forming mesh of the inventionaccording to FIG. 1,

FIG. 5 is a detail in cross section of a forming mesh according to theinvention,

FIG. 6 is a detail in cross section of a press felt according to theinvention,

FIG. 7 is a detail in cross section of a dryer fabric according to theinvention.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplification(s) set out hereinillustrate(s) one preferred embodiment of the invention, in one form,and such exemplification(s) (is)(are) not to be construed as limitingthe scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 4 show coverings which are produced from a construction kitof prefabricated web-shaped material layers 2, 3, 4, 11 and 15. All theweb-shaped material layers 2, 3, 4, 11 and 15 of the construction kitare formed in this embodiment as non-textile areal structures.

FIG. 1 shows in longitudinal section in machine direction sections of aforming mesh 1 according to the invention. The forming mesh 1 has apaper-side web-shaped material layer 2 through which the surface of thefibrous web formed on the forming mesh is essentially influenced, and amachine-side web-shaped material layer 3 through which the wear behaviorof the forming mesh 1 is essentially influenced. The machine-sidematerial layer 3 is thus a wear-stable material layer 3. In theembodiment in question the machine-side material layer 3 also hasdimension-stabilizing properties. The machine-side material layer 3 isthus also a dimension-stable material layer 3, as the result of whichthe dimension-stable and the wear-stable material layer 3 form anintegral unit.

Arranged between the paper-side material layer 2 and the machine-sidematerial layer 3 is a material layer 4 influencing the liquid absorptioncapacity.

The material layers 2 to 4 were taken from the construction kit ofprefabricated web-shaped materials layers 2, 3, 4, 11 and 15 in order toproduce the forming mesh 1 of the invention (see also FIGS. 2 and 3).

In the embodiment in question the material layer 2 is formed as anon-textile areal structure in the form of a penetrated film with holes5 and is produced from a material such as PE, PET, PPS or PA. Thepaper-side material layer 2 is undetachably joined, two-dimensionally atthe interface 7, to the material layer 4 influencing the liquidabsorption capacity by chemical ways through application of a bondingmedium 72 in the form of an adhesive 72.

The material layer 4 influencing the liquid absorption capacity isformed as a foamed layer with pores 9. In this case the pores have adefined size.

In the embodiment in question the material layer 3 is formed as anon-textile areal structure in the form of a penetrated film with holes6 and is produced from a material such as PE, PET, PPS or PA. Themachine-side material layer 3 is undetachably joined, two-dimensionallyat the interface 8, to the material layer 4 influencing the liquidabsorption capacity by chemical ways through application of a bondingmedium 72 in the form of an adhesive 72.

FIG. 2 shows in longitudinal section in the machine direction sectionsof a press felt 10 according to the invention. The press felt 10 isformed by the paper-side web-shaped material layer 2 known from FIG. 1,the machine-side web-shaped material layer 3 known from FIG. 1, thematerial layer 4 influencing the liquid absorption capacity known fromFIG. 1, by a material layer 11 likewise influencing the liquidabsorption capacity and by an anti-rewetting material layer 15.

All the material layers 2, 3, 4, 11 and 15 were taken from theconstruction kit of prefabricated web-shaped material layers 2, 3, 4, 11and 15 in order to produce the press felt 10 of the invention. The orderin which the individual material layers are stacked atop one another isdefined by the operating conditions for which the press felt 10 of theinvention is designed.

The material layer 2 is joined, at the interface 13, to theanti-rewetting material layer 15 by chemical ways through application ofa bonding medium 72 in the form of an adhesive 72.

The material layer 11 influencing the liquid absorption capacity isformed as a foamed layer with pores 12. In this case the pores 12 have adefined size which is greater than the size of the pores 9. Theanti-rewetting material layer 15 is joined, at the interface 16, to thematerial layer 11 influencing the liquid absorption capacity by chemicalways through application of a bonding medium 72 in the form of anadhesive 72.

The two material layers 4 and 11 influencing the liquid absorptioncapacity are undetachably joined together, two-dimensionally at theinterface 14, by chemical ways in the form of an adhesive bond 72.

The machine-side material layer 3 is undetachably joined,two-dimensionally at the interface 8, to the material layer 4influencing the liquid absorption capacity by chemical ways throughapplication of a bonding medium 72 in the form of an adhesive 72.

FIG. 3 shows in longitudinal section in the machine direction sectionsof a dryer fabric 20 according to the invention. The dryer fabric 20 isformed from the paper-side web-shaped material 2 known from FIGS. 1 and2 and from the machine-side web-shaped material layer 3 known from FIGS.1 and 2.

The two material layers 2 and 3 are undetachably joined together,two-dimensionally at the interface 21, by chemical ways in the form ofan adhesive bond 72.

FIG. 4 shows a detail in longitudinal section in the machine directionof the forming mesh 1 of the invention in the area of the two end areas30 and 31 of the forming mesh 1. In the situation illustrated, the twoend areas 30 and 31 are not yet brought fully into contact with eachother

As is evident from FIG. 4, the web-shaped material layers 2, 3 and 4 aremutually offset in machine direction and joined together,two-dimensionally, in sections. As the result, the two end areascomplement each other in form and function and can be joined togethertwo-dimensionally.

FIGS. 5 to 7 show coverings which are produced from a construction kitof prefabricated web-shaped material layers 41, 42 and 61.

FIG. 5 shows in cross section, meaning transverse to the machinedirection, sections of a forming mesh 40 according to the invention. Theforming mesh 40 has a paper-side web-shaped material layer 41 throughwhich the surface of the fibrous web formed on the forming mesh isessentially influenced, and a machine-side web-shaped material layer 42through which the wear behavior of the forming mesh 40 is essentiallyinfluenced. The machine-side material layer 42 is thus a wear-stablematerial layer 42. In the embodiment in question the paper-side 41 andmachine-side material layer 42 also have dimension-stabilizingproperties.

The material layers 41 and 42 are formed in this embodiment as textileareal structures in the form of weave structures 41 and 42.

The weave structure 41 is formed by the warp threads 45 and the weftthreads 44, whereby each weft thread 44 passes alternately under andover a warp thread 45 in order to form a smooth weave pattern, thuscreating a smooth contact area for the paper fibers.

The weave structure 42 is formed by the warp threads 46 and the weftthreads 47, whereby each weft thread 47 in a repeat unit passes undertwo consecutive warp threads 46 and then over one warp thread 46 inorder to form a particularly wear-stable weave pattern in which thehighly tensioned warp threads are protected by the weft threads 47against wear.

In the embodiment in question the two weave structures 41 and 42 arejoined together, two-dimensionally at the interfaces 48 and 19, bychemical ways through a bonding medium. Here the bonding medium itselfforms a foamed material layer 43, which is arranged between the twojoined weave structures 41 and 42. The foamed material layer 43 haspores 50 with a defined size. This means that the foamed material layer43 has the function of joining together the two weave structures 41 and42 in addition to the function of influencing the liquid absorptioncapacity.

FIG. 6 shows in cross section, meaning transverse to the machinedirection, sections of a press felt 60 according to the invention. Thepress felt 60 has the machine-side weave structure 42 known from FIG. 5and a fleece 61 with fibers 62.

The fleece 61 and the weave structure 42 are joined together at the twointerfaces 63 and 49 by the bonding medium 43 forming a material layer43. In the case of the press felt 60, the bonding medium again has thefunction of joining together the weave structure 42 and the fleece 61 aswell as the function of influencing the liquid absorption capacity ofthe press felt 60.

FIG. 7 shows in cross section, meaning transverse to the machinedirection, sections of a dryer fabric 70 according to the invention. Thedryer fabric 70 has the paper-side weave structure 41 known from FIG. 5and the machine-side weave structure 42 known from FIG. 5.

The two weave structures 41 and 42 are joined together,two-dimensionally, by chemical ways through a bonding medium 71 in theform of an adhesive 71.

While this invention has been described as having a preferred design,the present invention can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

List of Reference Numerals:

-   1 Forming mesh-   2 Paper-side material layer-   3 Machine-side material layer-   4 Material layer defining the liquid adsorption capacity-   5 Holes (paper-side material layer)-   6 Holes (machine-side material layer)-   7 Interface-   8 Interface-   9 Pores (material layer defining the liquid adsorption capacity)-   10 Press felt-   11 Material layer defining the liquid adsorption capacity-   12 Pores (material layer defining the liquid adsorption capacity)-   13 Interface-   14 Interface-   15 Anti-rewetting material layer-   16 Interface-   20 Dryer fabric-   21 Interface-   30 End area-   31 End area-   40 Forming mesh-   41 Weave structure (paper-side material layer)-   42 Weave structure (machine-side material layer)-   43 Bonding medium (material layer defining the liquid adsorption    capacity)-   44 Weft thread (weave structure)-   45 Warp thread (weave structure)-   46 Warp thread (weave structure)-   47 Weft thread (weave structure)-   48 Interface-   49 Interface-   50 Pores (bonding medium)-   60 Press felt-   61 Fleece-   62 Fibers (fleece)-   63 Interface-   70 Dryer fabric-   71 Bonding medium-   72 Adhesive

1-36. (canceled)
 37. A method for the modular production of coverings ofdifferent categories for use in one of paper machines, paperboardmachines and tissue machines, said method comprising the steps of:prefabricating a construction kit of web-shaped material layers;selecting a plurality of said web-shaped material layers from saidconstruction kit depending on a category and operating condition of thecovering to be produced; stacking said web-shaped material layers atopone another; and joining said web-shaped material layers to one anotherat least in sections, two-dimensionally, and in a manner that preventssaid web-shaped material layers from being detached.
 38. The methodaccording to claim 37, wherein said stacking of said web-shaped materiallayers comprises stacking them in an order which depends on the categoryand the operating conditions of the covering.
 39. The method accordingto claim 37, wherein said joining of said web-shaped material layerscomprises joining at least two web-shaped material layers togetherchemically.
 40. The method according to claim 39, wherein said joiningat least two web-shaped material layers together chemically is effectedby an interface-active bond.
 41. The method according to claim 40,wherein said interface-active bond is effected by one of vulcanizing,welding and melting.
 42. The method according to claim 39, wherein saidjoining at least two web-shaped material layers together chemically iseffected by adding a bonding medium.
 43. The method according to claim42, wherein said bonding medium is an adhesive.
 44. The method accordingto claim 42, wherein said bonding medium forms a material layer which isarranged between said joined material layers.
 45. The method accordingto claim 44, wherein said bonding medium forms a foamed material layerbetween said joined material layers.
 46. The method according to claim37, wherein said joining of said web-shaped material layers comprisesjoining at least two web-shaped material layers together mechanically.47. The method according to claim 46, wherein said joining at least twoweb-shaped material layers together mechanically is effected bypressing.
 48. The method according to claim 37, wherein said joining ofsaid web-shaped material layers comprises joining at least twoweb-shaped material layers together by a textile joining method.
 49. Themethod according to claim 48, wherein said textile joining method iseffected by one of sewing and pinning.
 50. A covering for use in one ofpaper machines, paperboard machines and tissue machines, said coveringcomprising: a construction kit including a plurality of prefabricatedweb-shaped material layers, each said web-shaped material layer beingconfigured dependent upon a category and operating conditions of thecovering, said plurality of prefabricated web-shaped material layersbeing stacked atop one another and joined to one another at least insections, two-dimensionally, and in a manner that prevents saidplurality of prefabricated web-shaped material layers from beingdetached.
 51. The covering according to claim 50, wherein saidweb-shaped material layers have a stacking order that is dependent uponthe category and the operating conditions of the covering.
 52. Thecovering according to claim 50, wherein said web-shaped material layersfulfill specific functions.
 53. The covering according to claim 50,wherein said web-shaped material layers are joined to one another insections via a bonding medium that fulfills specific functions one of onits own and in combination with at least one of said material layers.54. The covering according to claim 50, wherein the construction kit ofprefabricated web-shaped material layers comprises at least one materiallayer influencing the surface of a fibrous web and at least onewear-stable material layer.
 55. The covering according to claim 54,wherein said material layer influencing the surface of a fibrous web isone of a textile areal structure and a non-textile areal structure. 56.The covering according to claim 54, wherein said wear-stable materiallayer is one of a textile areal structure and a non-textile arealstructure.
 57. The covering according to claim 50, wherein theconstruction kit of prefabricated web-shaped material layers comprisesat least one dimension-stable material layer.
 58. The covering accordingto claim 57, wherein said dimension-stable material layer is one of atextile areal structure and a non-textile areal structure.
 59. Thecovering according to claim 50, wherein said construction kit ofprefabricated web-shaped material layers comprises at least one materiallayer influencing the liquid adsorption capacity.
 60. The coveringaccording to claim 59, wherein said material layer influencing theliquid adsorption capacity has one of a high liquid adsorption capacityand a low liquid adsorption capacity.
 61. The covering according toclaim 60, wherein said material layer with a high liquid adsorptioncapacity is one of a textile areal structure and a non-textile arealstructure.
 62. The covering according to claim 50, wherein saidconstruction kit of prefabricated web-shaped material layers comprisesat least one anti-rewetting material layer.
 63. The covering accordingto claim 62, wherein said anti-rewetting material layer is one of atextile areal structure and a non-textile areal structure.
 64. Thecovering according to claim 50, wherein said textile areal structure isone of a weave structure, a fleece, a thread plaiting, and a warpknitting.
 65. The covering according to claim 50, wherein saidnon-textile areal structure is one of: at least one of a structured filmand a penetrated film; at least one of a structured membrane and apenetrated membrane; and a foamed layer.
 66. The covering according toclaim 65, wherein said film is at least one of extruded and rolled. 67.The covering according to claim 65, wherein said foamed layer has adefined pore size.
 68. The covering according to claim 65, wherein saidfoamed layer has a plurality of defined pore sizes.
 69. The coveringaccording to claim 68, wherein said foamed layer has a defined pore sizein a transverse profile.
 70. The covering according to claim 50, whereinsaid web-shaped material layers are joined to one another with at leastone of a chemical and a mechanical bond.
 71. The covering according toclaim 70, wherein said web-shaped material layers are joined to oneanother by different bonding methods depending on the category, theoperating conditions, and the material layers to be joined together. 72.The covering according to claim 71, wherein said web-shaped materiallayers are mutually offset in one of a machine direction and atransverse machine direction and joined together, two-dimensionally, insections so that the covering forms two end areas which complement eachother in form and function and can be joined together.